Brake



P. M. FREER Feb. 5, 1946.

BRAKE Filed Feb. 16, 1944 2 Sheets-Sheet 1 I I I I I I llll I I llllnll INVENTOR.

PHELPS MFREER ATTORNEYS Feb. 5, 1946. P, M. {FREER 2,393,980

BRAKE Filed Feb. 16, 1944 I 2 Sheets-Sheet 2 Will/III! V'INVENTOR. PHELPS M.FREER BY I ATTORNEYS Patented Feb. 5, 1946 UNITED STATES PATENT OFFICE "BRAKE Phelps M: Freer, lj etroitjlvlich. Ai-ipueieafi'emny 1e, 1'944,"Seiial No. 522,635

4' Claims.

The invention relates to brakesfa'nd refers more particularly to brakesof that-type having a'brake drum and aninternal brake member engagea'ble with the drum. I I c,

The invention hasfor"anj'objectto provide an improved brake of relatively "simple construction. The 'inventi'on'jhas for another "objectto 'so construct the brakejthat the brake member is movable against'andj away from the' br'ake drum by means comprising a resilient member. I I

The inVentiOn has for furtherobjjec'ts to so construct the brakefthat the resilientmember is bowed; and'to so constructjthe brake that the brake member has separable ends": and the resilientjmember normally exerts a force on one'end jof the'brake member tending to more 'the same generally 'circu'mferentially and radially'of the drum. I I I I These and other objects'of the'invention will become apparent from the following description, taken 'in connection with the accompan ying drawings, in which: I c I I I I Figure 1 is an inboard elevation, 'partlyf broken away and with the'wheel support omittedfof a brake embodying the invention; I I I Figure 1A is an inboard leyat ion, withthe backing plate omitted, of a portion of the brake. Figures 2 and 3' are edgeeleyations, partly broken away; Q I

Figures 4, 5, 6, land 8 are cross sections on the lines 44, 5-5, 6- 6, 1-1 and 8-8, respectively, ofFigure1. I

The brake comprises the brake and an internal brake member having separable ends and ,formed of the brake shoes 2, 3f'and 4 arranged in end to end relation and engageable with the annular brake flange'fi of the The drum has .at the outboard edge of itsbrake flange the radially inwardly extending flange B which is adapted tobe attached to or mounted on the wheel 1 by suitablemeans, sueh as the bolts 8. The whee l is journaled onLthe axle 9 of thestationary support n which has the fixedradial flange II. The wheel normallytrotates in the direction of the arrow in Figure 1.

The brake shoes 2, 32nd 4 have T-section'bodies with the webs l 2 and the axial'flanges j l3,"to which latter the brake linings I4 are secured. The brake shoe 2 is pivotally connected to't'hebrake 'shoe 3 and the brake shoe 3 is 'p'ivotally connected to the brake shoe 4 by the' r iVetslS whiehextend through axially offset end portions'of'the' webs o t k hp she.br ke hoesarepanchored by the anchor I 6 lobatedatthe normally trailing endl'of' the "brake shoef l "fis brake shoe2 againstthe brake'flangeii'ofthe drum, I have provided the resilient bowed member 22 which is operatively connectedto'the'normany leading end of the brake shoe 2 and"also*to thebackingplate l8 and is bowed fin the direction opposite to that of the normal rotation of the drum. Theoperative connections are in different radial planes of the brake with'the operatiyeconnection between the resilient member and the brake shoe positioned with respect to'thelradial 'plane of the operative connectionbetween the resilient" member andjthe backing plate a radial planefjlocated angularly or circumferentially in the direction opposite to that of the normal rotation ofthe drum'so that when the bow "is flattened the movement imparted to thenormall leadin end of the brake 'shoeZ has a consi'derable radial component, I The resilient bowed member, as shown in the present instance, isf'a 'wirespring and has the bowed portions 23 each of which has the coils ,24 and 25 at its en ds and the coil 26 at substantially its middle. The resilient bowed member also has the integral U- shaped portion 21 formed with aleg extending frorneach'coil' 25 and atransverse part 28 connecting'f each leg. 29 is a pinextending transversely through the normallyleading end of the Web J2 of the brake shoe 2 and having' i ts end portions extending throughthe coils24, -3ll' is a pin extending substantially parallel to the pin '29 transversely through the web'3l of the channelshaped bracketj32 which its foot flanges" suitably secured to the backing plate l8 as by being welded'thereto. The 'pin3n has its end'portions extending through the' coils 25. 33is 'an'oth er'jjin extending substantially; paralleljto thepins 2 9 "and,

.3 a ha n ts and or n? z i i @9 1 2 The P1 1 ,3? 54 exte t .5 m gh 'iree'endof the pistonrod'34 whichislocated'be tween the coils 26. ,The portionsof the pins 29, 30 and 33 engaged by the coils are reduced to form necks so that the pins and coils are properly positioned axially of the brake. The piston rod 34 forms part of thefluid pressure operated actuator or wheel cylinder 35 which comprises the cylinder 36 mounted on the backing plate I8, the piston 31 slidable within the cylinder and the piston rod 34. A suitable sealing cup 38 is preferably provided within the cylinder 36 and resiliently held against the head of the piston 31 by the coil spring 39. v

To move the normally trailing end of the brake shoe 4 against the brake flange of the drum, the channel-shaped member 40 is fixedly secured to .the normally leading end of the web l2 of the brake shoe 2. The channel-shaped member embraces and extends circumferentially beyond the normally leading end and also embraces the nor- -mally trailing end of the web I2 of the brake shoe 4. The bottom of the channel-shaped mem .ber is concentric with the brake shoes and is engageable with the radially inner edge of the Web'of the brake shoe 4 so that when the normally leading end of the brake shoe 2 is moved against the brake flange 5 of the drum the channel-shaped member moves the normally trailing end of the brake shoe 4 against the brake flange of the drum. As shown in the present instance, the normally leading end of the web of the brake shoe 2 and the normally trailing end of the web of the brake shoe 4 are formed with enlargements having their adjacent edges 2' and 4', respectively beveled and arranged so that theenlargement of the web of the brake shoe 4 extends radially inside the enlargement of the web of the brake shoe 2.

In operation, when braking fluid is forced into the fluid pressure operated actuator or wheel cylinder 35 the resilient bowed member 22 is fiattened and acts upon the normally leading end 4 of the brake shoe 2 to move the same generally radially outwardly and away from the normally trailing end of the brake shoe 4. Also the channel-shaped member 40 moves the normally trailing end of the brake shoe 4 generally radially outwardly in'a direction as determined by the anchor l6 engaging the side edges of the opening I9.

To retract the normally leading end of the brake shoe 2, the transverse part 28 of the U-shaped portion 21 of the resilient bowed member 22 is positioned to abut the side wall of the channelshaped bracket 32. The arrangement is such that the coils 25 are subjected to torsion and the legs of the U-shaped portion 21 and also the parts of the bowed portion 23 adjacent the coils 25 are flexed during the flattening of the bowed portion so that when the pressure of the braking fluid is relieved the coils, the legs and the parts return to their normal positions because of their inherent resiliency and serve to move the nor mally leading end of the brake shoe 2 generally circumferentially and radially inwardly. To retract the normally trailing end of the brake shoe 4, the secondary leaf spring 4| is fixedly secured to the backing plate l8 and extends throughthe opening 42 in the normally trailing end of the 'web 12 of the brake shoe 4 and abuts the radially the brake shoe 4 against the channel-shaped member 40. It will be seen that the retraction of the two ends of the brake shoes 2 and 4 serves to effect the'retraction also of the intermediate brake shoe 3.

The brake may also be applied mechanically by means of the cable 43 which has the ball 44 secured thereto. .The ball abuts the outside lever 45 fixed upon'the shaft 46 journaled in the backing plate 18. 41 is a second lever also fixed upon the shaft-and located withinthe brake and engageable with the coils 2B, the construction being such that upon pulling the cable 43 the lever 45 is swung, the shaft 45 is rotated, and the lever 41 is swung to flatten the resilient bowed member 22.

48 is an eccentric stop rotatively adjustably secured to the backing plate I8 by means of the cap bolt 49 threaded to the backingplate. The eccentric is engageable with the outside lever 45 when the latter is in its retracted position.

What I claim as my invention is:

l. A brake comprising a brake drum, an internal brake member, a stationary member and means for moving said brake member against said drum comprising a spring having coils near its ends and an intermediate coil, an actuating rod, pins extending through said first mentioned coils for operatively connecting said spring to said brake member and stationary member and another pin extending through said intermediate coil for operatively connecting said spring to said actuating rod, said pins having reduced portions forming necks encircled by said coils to .position i ary member and brake member and having a normally laterally offset knee portion resiliently restrained from'bending and actuating means engaging said knee portion to rock said toggle lever means as a unit about its stationary pivot. thereby movingsaid brake member into frictional con- :tact' with said drum and under braking load bending said knee portion to efi'ect a toggle lever action.

3, In a brake, the combination with, a brake drum, an internal brake member and a stationary member; of operating means thereforincluding a resilient member forming in effect a toggle lever extending in a generally radial direction with respect to said brake drum with its inner and outer ends pivotally connected respectively to said stationary member and brake member, said resilient member being fashioned to have a normally laterally offset knee portion and the resiliency being such as to normally restrain said knee frombend ing and actuating means engaging said knee portion to rock said resilient member about itsstationary pivot without'bending the knee'to move said brake member into frictional contact with said drum and the further movement of said actuating means under braking 'load bending said knee to effect a toggle lever action." i

l. In a brake, the combination with a'brake drum, an internal brake member and asta'tionary member; of a resilient toggle lever member formed of a rod return bent to have substantially, parallel spaced leg portions with three coils in each leg located respectively adjacent to said return bend, adjacent the opposite and inter mediate said ends, the intermediate coils being laterally offset from the end coils, pins engaging the opposite end coils to pivotally connect the same respectively with said stationary member and brake member with said legs extending in a generally radial direction with respect to said brake drum, a pin engaging said intermediate coils and an actuator connected to the latter pin for rocking said resilient member as a unit about said stationary pin thereby moving said brake member into frictional contact with said drum and under braking load bending said member about said intermediate coils to effect a toggle lever action PHELPS M. FREER. 

